Information Requests Monitoring System

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Request ID: 143
Request From: Steve Toth
Date Requested: Jan 05, 2006
Request: Note the following request for information on dimethoate use on 24 crops (with less than 1% of crop treated). Please pass along this request to the experts in your states/territories and submit any responses to the Information Requests Monitoring System by January 19, 2006. Thanks for your help! Steve Toth ---------------------------------------------- EPA is in the early stages of preparing risk mitigation decisions for dimethoate. Because of the August 2006 FQPA deadline to reassess all tolerances, dimethoate is scheduled by EPA for final decisions within the next several months. Malathion is on a similar track. I am contacting you instead of my OPMP colleague, Phil Poli, who is on extended leave. EPA has requested USDA assistance in obtaining benefits information for 24 crops with less than 1% crop treatment with dimethoate. EPA will be initiating outreach directly for other commodities of interest. Per EPA, the crops with less than 1% crop treated are: alfalfa, asparagus, carrots, corn, cotton, grapefruit, onions, oranges, spring wheat, peanuts, pears, plums and prunes, pumpkins, sorghum, squash, strawberries, sugar beets, sunflowers, sweet corn, tobacco, wheat, soybeans, and safflower. Please respond in three weeks to the following EPA questions and add your contact information as well should follow-up be required as EPA prepares for risk mitigation decisions. By answering as many questions as possible, EPA will be able to further refine the risk assessment for dimethoate by improving the ecological risk and drinking water numbers, address REI issues and obtain needed benefits information. The answers to some questions may be contained in existing crop profiles and Pest Management Strategic Plans (PMSPs) but EPA has not had opportunity to collate the information; focusing instead on the crops with larger percent crop treatment. The short time frame precludes OPMP from collating the information as well so we are relying on experts in the field. Per EPA to OPMP, "Please consider the best way for us to work together to get at this information quickly, since our time frame is short. If a use is to be maintained, we will need some documentation to support that use in light of existing risks. Specifically, it would be helpful if growers could provide answers to as many of the following questions as possible." (1) In what region (state/county, etc.) of the US does the use occur? (2) What are the pests that they feel are critical for the low usage of dimethoate use? (3) What are the details of their typical usage pattern (e.g., number of applications per season, use rate per application, acres treated, time of application in the season?) (4) What worker activities typically occur when they need to apply dimethoate? (5) What alternatives, if any, do they feel they would have to use to replace dimethoate? Thank you again for your assistance. Please forward this request to others as appropriate. I will keep you apprised and will be sending out a similar request today for malathion. Please do not hesitate to contact me if you have any questions or comments. Teung F. Chin, Ph.D. Biological Scientist Office of Pest Management Policy Agricultural Research Service United States Department of Agriculture USDA Animal & Plant Health Inspection Service 4700 River Road, Unit 149 (Room 3D-06.8) Riverdale, MD 20737-1237 Phone (301) 734-8943 Fax (301) 734-5992 Teung.F.Chin@usda.gov http://www.ars.usda.gov/opmp

Responses
Responder: Mark Matocha
State: TX
Date Requested: Jan 12, 2006
Response: Notes on critical dimetholate uses in Texas crops Summarized January 11, 2006 Provided by TCE, Texas A&M System Grain sorghum: Particularly important for several pests Yellow sugarcane aphid (YSA), dimetholate is important due to the widespread range of this pest and somewhat limited alternatives for control when out breaks occur. Rice stink bug (RSB) - label states “do no use after heading” . But use within that time frame is important in some years when out breaks occur. Do not observe any crop damage from pesticide but RSB losses can be severe. Spider mite, Banks grass mite, and occasional green bug control - in sorghum in High Plains region (in irrigated and dry land production from Lubbock, north to OK panhandle region). Particularly important for Banks grass mite control - as a stand alone treatment. Key for good control is assuring good spray coverage on the crop foliage. Use in Coastal Bend area of Texas (Corpus Christi region) - dimethoate use has been limited in past six years but the product is important when out breaks occur. This occasional use probably accounts for this crop being on the “less than 1%” list at EPA. Corn. Spider mite and Banks grass mite control Banks grass mite control - dimetholate alone gives weak to moderate control but is synergistic when applied with Warrior or Capture, giving good 7 to 14 day control (depending on stage of crop growth and environmental conditions). Difference between control in corn and sorghum is due to structure (less plant coverage due to wider foliage). Resource People High Plains region: Mr. Greg Croholm, IPM Extension Agent POB 680 Plainview, Texas 79073-0680 806-291-5274 Coastal Bend Region: Dr. Roy Parker, Area Extension Entomologist Texas A&M Center at Corpus Christi 512-265-9201

Responder: Scott Stewart
State: TN
Date Requested: Jan 14, 2006
Response: Dimethoate, although used on limited acreas in Tennessee cotton fields, is a valuable product for cotton producers in parts of the MidSouth and Southeast. It provides inexpensive and effective control of plant bugs and spider mites in some circumstances. The need for short-duration, late-season control of mites is sometimes needed throughout the region. Alternative for spider mite control are considerably more expensive and include Zephry, Oberson, Capture, Kelthane, Denim, Comite and Acramite. Other than Capture, dimethoate is the only miticide that also provides reasonable control of plant bugs and stink bugs (common pests of cotton). In this way, dimethoate has a unique niche. Although spider mites are a rare problem in soybean, there are essentially no effective alternatives to dimethoate for mite control in this crop. When used, dimethoate is rarely applied more than twice at a maximum application rate of 0.25 Lb AI/Acre. At the time of application, normally mid to late season, scouting is the only activity that typically occur in fields. Dr. Scott Stewart Associate Professor IPM Specialist University of Tennessee (731) 425-4709 sdstewart@utk.edu

Responder: Mark Mossler
State: NC
Date Requested: Jan 19, 2006
Response: This is a fairly easy question for Florida. No dimethoate is used for these listed crops. It is used for some other ag crops and ornamentals. Will try to confirm this same trend in PR and the VI. Mark Mossler

Responder: Steve Toth
State: NC
Date Requested: Jan 19, 2006
Response: Very little use of dimethoate on cotton in North Carolina. We have this product listed for thrips control in the North Carolina Agricultural Chemical Manual, but its use by cotton producers is almost non existent (say ~1%). Dimethoate is also labeled for plant bugs on cotton, but we do not recommend it in North Carolina. Jack Bacheler Extension Entomologist - Cotton North Carolina State University

Responder: Holly Gatton
State: VA
Date Requested: Jan 19, 2006
Response: I’m attaching the file that Mike and I put together on dimethoate use in Virginia. Holly A. Gatton Project Manager Virginia Tech Pesticide Programs Department of Entomology 34 Agnew Hall, MC 0409 Blackburg, VA 24061 Email: hgatton@vt.edu Phone: 540-231-2086 Fax: 540-231-3057
Attachment included in response [Download]

Responder: Charles Luper
State: OK
Date Requested: Jan 19, 2006
Response: For Oklahoma Dimethoate is not very important to Alfalfa and peanuts. It is used on less than 5% of the aceaage and alternatives exist according to Dr. Phil Mulder. For Oklahoma Dimethoate biggest importance would be to the wheat acreage. Dimethoate is a very imporant tool for aphid control. It is a very cost effecient tool versus alternatives for aphid control on wheat.

Responder: Darrell Hensley
State: KY
Date Requested: Jan 20, 2006
Response: KENTUCKY GRAIN CROPS Douglas W. Johnson, Extension Entomologist UK-IPM Coordinator UK-REC 1205 Hopkinsville St. Princeton, KY 42445-0469 Voice: 270/365-7541 x 214 Campus: 7-9503 x214 FAX: 270/365-2667 E-Mail: doug.johnson@uky.edu This response concerns the following grain crops: Sorghum (grain), wheat(soft red winter), soybeans (full season and double-crop). General: Dimethoate is rarely used on any grain crop in Kentucky. It's most important use would be against spider mites outbreaks on soybean. Little effect will occur from removing sorghum or wheat (soft red winter) from the label. However, removing the product from soybean could have a very important result. (1) In what region (state/county, etc.) of the US does the use occur? KENTUCKY, PRIMARILY WESTERN 1/3 OF THE STATE. (2) What are the pests that they feel are critical for the low usage of dimethoate use? TWO SPOTTED SPIDER MITES ON SOYBEAN (3) What are the details of their typical usage pattern (e.g., number of applications per season, use rate per application, acres treated, time of application in the season?) THIS IS A SPORADIC BUT IMPORTANT PROBLEM. THE OUTBREAKS ARE USUALLY A RESULT OF DROUGHT CONDITIONS. IF THE OUTBREAK OCCURS TREATMENT WILL BE AT THE FULL LABEL RATE AND 1-2 APPLICATIONS PER AFFECTED AREA. BECAUSE OF KY's GENERAL WEATHER PATTERNS OUTBREAKS WILL USUALLY OCCUR IN THE AUGUST - SEPTEMBER TIME FRAME. HOWEVER, BECAUSE WE HAVE BOTH FULL SEASON AND DOUBLE CROP BEANS IT COULD OCCUR ALMOST ANY TIME OF THE GROWING SEASON. ACRES TREATED WILL DEPEND UPON HOW WIDE SPREAD THE DROUGHT THUS OUTBREAK BECOMES. (4) What worker activities typically occur when they need to apply dimethoate? VERY FEW WORKER ACTIVATES AFTER SPRAYING. SCOUTING WILL OCCUR TO DETERRING IF / WHEN / WHERE TREATMENTS ARE NEEDED. GRAIN PRODUCTION IN KY IS A HIGHLY MECHANIZED PRODUCTION SYSTEM. (5) What alternatives, if any, do they feel they would have to use to replace dimethoate? AT THIS POINT ONLY LORSBAN (CHLORPYRIFOS) IS LABELED FOR THIS PEST. BECAUSE OF THE SPORADIC NATURE OF THE PROBLEM, AND DIFFICULTY IN OBTAINING ADEQUATE CONTROL, I THINK IT UNLIKELY THAT COMPANIES WILL SEEK TO EXPAND EXISTING LABELS TO INCLUDE SPIDER MITES. THUS REMOVE ONE OF THE CURRENTLY LABELED COMPOUNDS WILL SIMPLY REDUCE THE NUMBER OF TOOLS AVAILABLE AND MAY INCREASE CHANCES OF RESISTANCE TO THE REAMING TOOL. -------------------------- Darrell Hensley University of Tennessee 2431 Joe Johnson Drive, 205 PSB Knoxville, TN 37996-4560 Phone (865) 974-7958 Fax (865) 974-8868 email: dhensley@utk.edu

Responder: Frank Hale
State: TN
Date Requested: Jan 24, 2006
Not Important/Relevant to my state(s)
Response: Dimethoate is not in our Extension recommendations for the listed crops. The loss of its use on these crops would not significantly harm our growers. Other alternative insecticides are available for the listed crops.

Responder: Frank Hale
State: TN
Date Requested: Jan 24, 2006
Response: I wanted to amend my previous comments to state that the listed crops to which I was referring were the fruit and vegetable crops and tobacco with which I work. On those crops, dimethoate is not an important insecticide in Tennessee. I am not speaking for the other listed crops.

Responder: Charles Luper
State: OK
Date Requested: Jan 26, 2006
Response: Dr. Tom Royers reponse to the Diemthoate needs is included in the attached file.
Attachment included in response [Download]

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